Description
Hot Rods Yamaha Blaster +4mm Stroker Crankshaft
The Hot Rods Yamaha Blaster stroker crankshaft is designed for high-performance YFS200 engine builds requiring more displacement, torque and overall power. Increasing the crankshaft stroke by 4mm changes the factory 57mm stroke to 61mm and produces approximately 209cc with a standard 66mm-bore piston.
The additional stroke increases engine displacement without requiring a big-bore cylinder. When combined with properly matched cylinder porting, head machining, carburetion and exhaust components, this stroker crankshaft can deliver a strong increase in torque and usable power.
This is Hot Rods part number 4105 and fits Yamaha Blaster YFS200 models from 1988 through 2006.
Product features
- Genuine Hot Rods performance crankshaft
- Hot Rods part number 4105
- 4mm increase over the factory stroke
- 61mm final crankshaft stroke
- Approximately 209cc with a standard 66mm piston
- Complete factory-assembled crankshaft
- Designed for performance Yamaha Blaster engine builds
- Connecting-rod side clearance: 0.40–0.85mm
- Fits every Yamaha Blaster model year from 1988–2006
Machining is required
This Yamaha Blaster +4mm stroker crankshaft is not a bolt-in component. The following machine work is required for proper installation:
- Engine cases must be trenched for connecting-rod clearance
- Crankcase clearance must be checked carefully because factory castings can vary
- Cylinder-head combustion chamber must be machined 2mm deeper
- Squish clearance and cranking compression must be measured during assembly
- Cylinder port timing should be checked and corrected for the increased stroke
- Complete engine assembly must be checked for internal clearance before operation
Incorrect installation can cause severe engine damage. This crankshaft should be installed by an experienced Yamaha Blaster engine builder.
Ken OConnor Racing machine-shop services
Ken OConnor Racing can perform the case trenching, head machining, cylinder porting and complete engine assembly required for this Hot Rods stroker crankshaft. Every stroker combination should be measured and set up as a complete system rather than assembled using assumed clearances.
Contact KOR if you would like this crankshaft installed as part of a professionally machined Yamaha Blaster performance engine.
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Hot Rods |
| Manufacturer part number | 4105 |
| Application | Yamaha YFS200 Blaster |
| Model years | 1988–2006 |
| Engine type | Two-stroke |
| Crankshaft type | Stroker |
| Stroke increase | +4mm |
| Final stroke | 61mm |
| Displacement with 66mm bore | Approximately 209cc |
| Connecting-rod side clearance | 0.40–0.85mm |
| Installation | Professional machining required |
Important ordering information
This listing is for the Hot Rods stroker crankshaft assembly. Crankshaft bearings, seals, gaskets and other engine-rebuild components are not included unless specifically selected or stated elsewhere on the order.
Verify all engine clearances during assembly. Final displacement will change if the crankshaft is combined with an oversized or big-bore piston.
Frequently asked questions
Will this crankshaft fit a stock Yamaha Blaster?
It fits 1988–2006 Yamaha Blaster YFS200 engines, but it will not fit without machine work. The cases must be trenched, and the cylinder head must be modified for the additional stroke.
What displacement does the +4mm crank produce?
The 61mm stroke produces approximately 209cc when used with a standard 66mm-bore piston. A larger piston will increase displacement further.
Does this crankshaft require a spacer plate?
This combination is designed around machining the cylinder head combustion chamber 2mm deeper. The entire engine combination must still be measured for correct squish clearance, compression and port timing.
Can Ken OConnor Racing install this crankshaft?
Yes. KOR can perform the required case trenching, cylinder-head machining, porting and complete engine assembly.
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